Surface enhanced Raman scattering substrate

Abstract

An apparatus includes a substrate having a base and a plurality of pillars extending from the base where the pillars are configured to define a nano-array, a dielectric disposed on the base, and a plasmonic coating disposed on a surface of the dielectric and on one or more of the pillars.

What is claimed is: 
     
       1. An apparatus, comprising:
 a substrate including a base and a plurality of pillars extending from the base, the pillars having end portions configured to define a nano-array; 
 a dielectric layer disposed on the base and at least partially enclosing the pillars, the dielectric layer having an upper surface, the end portions of the pillars extending beyond the upper surface of the dielectric layer; and 
 a plasmonic coating disposed on a surface of the dielectric layer and on the end portion of one or more of the pillars. 
 
     
     
       2. The apparatus of  claim 1 , wherein the plasmonic coating is discontinuous such that a gap is defined in the plasmonic coating adjacent an intersection of the end portion of the one or more pillars and the upper surface of the dielectric layer. 
     
     
       3. The apparatus of  claim 2 , wherein the end portions of the pillars each define a tapered nanotip portion. 
     
     
       4. The apparatus of  claim 2 , wherein the upper surface of the dielectric layer is planar. 
     
     
       5. The apparatus of  claim 2 , wherein the one or more pillars comprise an epitaxial layer. 
     
     
       6. The apparatus of  claim 1 , wherein the end portions of the one or more pillars each define a nanosphere comprising the plasmonic coating with portions thereof disposed on the dielectric layer. 
     
     
       7. The apparatus of  claim 6 , wherein adjacent nanospheres on the end portions of the one or more pillars are in spaced relation to define a gap therebetween. 
     
     
       8. The apparatus of  claim 1 , wherein the substrate includes semiconductor components. 
     
     
       9. A method, comprising:
 forming a substrate including a base and a plurality of pillars extending from the base and arranged in spaced relation; 
 removing material from end portions of the pillars to define a nano-array; 
 depositing a dielectric on the base of the substrate; 
 coating with a plasmonic film the end portions of the pillars defining the nano-array and the dielectric; and 
 removing plasmonic film segments around each of the end portions of the pillars defining the nano-array. 
 
     
     
       10. The method of  claim 9 , wherein removing material from the end portions of the pillars includes subjecting the end portions to a thermal oxidation process. 
     
     
       11. The method of  claim 9 , wherein removing material from the end portions of the pillars includes subjecting the end portions to an etching process. 
     
     
       12. The method of  claim 9 , wherein removing the end portions includes forming tapered nanotip portions of the pillars. 
     
     
       13. The method of  claim 12 , wherein removing plasmonic film segment includes applying a non-conformal deposition of a sacrificial material onto the tapered nanotip portions, and performing at least one etching process to remove the sacrificial material adjacent the tapered nanotip portions to expose and remove the plasmonic film segments to define a gap around the nanotip portions devoid of plasmonic film. 
     
     
       14. The method of  claim 12 , wherein coating with the plasmonic film includes directional etching to form a nanosphere on each of the tapered nanotip portions of the pillars. 
     
     
       15. The method of  claim 9 , further including depositing a liner on sidewalls of the pillar prior to depositing the dielectric on the base of the substrate. 
     
     
       16. A method, comprising:
 forming a substrate including a base and a plurality of pillars extending from the base and arranged in spaced relation; 
 applying a liner onto the pillars and the base; 
 depositing an oxide fill on the base to fill gaps between the pillars; 
 planarizing the oxide fill to be coplanar with the pillars; 
 removing at least a portion of the oxide fill and the liner to at least partially expose the pillars; 
 removing material from end potions of the pillars by one of an oxidation process and etching process to form tapered nanotip portions; 
 depositing a second oxide fill onto the base of the substrate; 
 exposing the tapered tip portions of the pillars from the second oxide fill; 
 coating with a plasmonic metal film the tapered tip portions of the pillars and an exposed surface of the second oxide fill; and 
 removing plasmonic film surrounding each tapered tip portion of the pillars to isolate the plasmonic film on the tapered tip portions from the plasmonic film on the surface of the second oxide film. 
 
     
     
       17. The method of  claim 16 , wherein removing the plasmonic film includes applying a non-conformal deposition of a sacrificial material onto the tapered nanotip portions, and performing at least one etching process to remove the sacrificial material adjacent the tapered nanotip portions to expose and remove the plasmonic film segments to define a gap around the nanotip portions devoid of plasmonic film. 
     
     
       18. The method of  claim 16 , wherein forming the substrate includes growing an epitaxial layer on the substrate such that the pillars each include an epitaxial layer. 
     
     
       19. The method of  claim 18 , further including removing material from end portions of the pillars includes subjecting the epitaxial layer to a wet oxidation process. 
     
     
       20. The method of  claim 16 , further including directional etching the plasmonic film to form a nanosphere on each tapered nanotip portion.